Air conditioning system



Nov 19, 1940. A- PHIUPP 2,222,240

AIR CONDITIONING SYSTEM Original Fil ed Nov. 14, 1933 y INVENTOR.

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11* Nov. 19, 1940 UNITED STATES PATENT OFFICE 2,222,24ll connrrionme srs'rn Lawrence A. Philipp, Detroit, Micln, assignor, by

mcsne assigmnents, to Nash-Kclvinator Cornotation, Detroit,

Maryland Mich,

a corporation oi 12 hlaims.

The present invention relates to refrigeration and more particularly to air conditioning system in which a refrigerating apparatus is utilized for conditioning the air.

One of the objects of the present invention is to provide a refrigerating apparatus employing a plurality of evaporators of the type in which the flow of refrigerant to the same is responsive to the condition of the refrigerant in the respective evaporator, and circulating refrigerating medium through the evaporators in such a manner that the temperature difierential between the same may be attained by providing for different suction pressures at the outlets of the evaporators, and to provide for interconnecting the outlets oi the evaporators so as to at times maintain a substantially uniform temperature of the evaporators; to control the interconnection of the outlets or the evaporators in response to the relative humidity of the air which is to be conditioned by the evaporators; to connect a plurality of evaporators with a plurality of sources of low pressure and to at times connect each evaporator individually with a source of low pressure and at times interconnect the evaporators with one another and with a plurality of these sources of reduced pressure.

Other and further objects and advantages will be apparent from the following disclosure, reference being had to the accompanying drawing wherein a preferred form of embodiment of the present invention is clearly shown.

The figure in the drawing represents more or less diagrammatically my improved reirigerat ing apparatus and air conditioning system.

Referring to the drawing, I have illustrated the air conditioning system as being applied to cooling a room such as anoflice or a room in a dwelling. The room is indicated as ill and a wall it and a floor 22 of the room are shown. A cablnet 24 is disposed within the room 20 and is provided with an air inlet opening 25 and an air outlet opening 26. A partition 29 depends from the top wall of the cabinet and extends from the front to the rear of the cabinet for directing air. A fan 21' driven by a motor 28 causes air to circulate through the cabinet 24. Any form of heat absorbing element may be employed and I have herein illustrated an element comprising evaporators or evaporator sections 30 and 3|, each including a coil provided with fins 32 for increasing the heat absorbing surface 3|]. The evaporator 3| has approximately as much heat absorbing surface as evaporator 30. Air from the room 20 enters the cabinet 24 through the inlet 25 and approximately one-half oi the air is forced over the evaporator it and the other half thereof is forced over the evaporator ill and then out oi the cabinet through the opening it. The means for circulating refrigerating medium through the heat absorbing elements provides a plurality of sources of reduced pressure and is herein shown as comprising a multiple cylinder compressor it having a cylinder it and a cylinder t'l. This compressor is of the reciprocating type and the cylinder it is provided with an inlet itand the cylinder it is provided with an'inlet at. The inlet it also communicates with the cranlr case of the compressor for withdrawing gaseous refrigerant therefrom. The outlets for the compressed rluid are connected with one another at it. The compressor is driven by a motor t2 and a reduction gearing may be employed between the motor it and compressor it it so desired.

Gaseous refrigerant which enters the inlets 3d and it is compressed by the compressor, forced into a condenser it where it is cooled and liquefled and then into a receiver t l whence it is conducted by a pipe ti and branch pipes it and ill to expansion valves it and it. 'llhese valves it and it control the flow. of refrigerant to their respective evaporators it and it in accordance with the condition of the refrigerant in the respective evaporators. Each valve is responsive to the pressure within an evaporator. A reduction in pressure within the evaporator tends to open the valve to admit liquid refrigerant to the evaporator but this opening of the valve is modifled by a thermostat d. The thermostats 5d are bonded to the outlets oi the evaporatorstll and it and are connected to the baclr side of the expansion valves 4t and 19 by tubes iii. The thermostats 5t) and 5t contain a volatile fluid and therefore vary the pressure on the back sides of the valves 4d and 49 and are adjustedto prevent or substantially prevent the flow of refrigerant to the evaporators when vaporization of refrigerant is taking place at the outlets of the evanorators. Such valves are known in the art as thermostaticexpansion valves. The outlet of evaporator 3i is connected to inlet 38 of cylinder 36 by a pipe 55. A, pipe 51 connects the outlet of evaporator 30 to the chamber 58 of an oil trap 60 and gaseous refrigerant passing from evaporator 30 flows through pipe 51, chamber 58 and through a pipe St to the inlet 3!! of cylinder 31.

An oil outlet of chamber 58 is connected by a pipe 63 with the crank case of compressor 35 and is arranged to deliver entrained oil to the tra s case. The outlet'of the oil trap is con til ' midity of the air in the room 20.

trolled by a float actuated valve 64 which opens the outlet after a predetermined quantity of oil is collected within the chamber 58.

Suction pipes 55 and 51 for evaporators 3| and are arranged to be interconnected by pipes 65, valve 66 and pipe 61. The valve 66 comprises a solenoid core 68 which is arranged to open and close the valve 66. This core 68 when raised by an electro-magnet 69 opens the outlet of the valve 66 to establish connection between the pipe 55 and pipe 51.

Gaseous refrigerant which is withdrawn from evaporators 30 and 3| is compressed by the compressor condensed in the condensers 43 and is delivered to thermostatic expansion valves 48 and 49. A part of the refrigerant vaporizes in evaporator 38 and the vaporized refrigerant passes through pipe 51 whence it is delivered to the inlet 39 of cylinder 3'! and, part of the refrigerant vaporizes in evaporator 3!. The gaseous refrigerant then passes by way of pipe 55 to the inlet 38 of cylinder 36. Moisture from the air condenses on the evaporators 38 and 3| and falls to the bottom of cabinet 24 and is conducted from the cabinet through a drain pipe 78.

The quantity of refrigerant circulated through the refrigerating apparatus and the relative quantities or rate of flow of refrigerant through the evaporators 36 and 31! are governed by the condition of the air in the room 29. The motor 62 which drives the compressor 35 is cyclically operated and the duration of the phases of operation of the refrigerating apparatus is controlled by the temperature and the relative hu- It is well understood that comfortable temperature varies with the relative humidity of the air. For example, a temperature of 83 F. of the air at 50% relative humidity is considered a comfortable condition of the air. In accordance with the present invention, I desireto maintain the air between 82 F. and 84 F. when the relative humidity of the air is approximately 50% or less and for this purpose I provide a thermostat 12 which is connected by a tube 13 to a pressure operated snap switch 14. This switch M is arranged to close its contacts when the temperature of the air attains 84 F. and. opens its contacts when the temperature is decreased to 82 F. The thermostat bulb l2 and tube 13 contain a volatile fluid which expands and contracts due to increase and decrease in temperature. When the contacts of the switch M are closed a circuit is completed to the motor 62. Switch 74 first closes a relay circuit as follows: main 16, wires l7 and i8, switch M, wire l9, normally closed switch 80, electro-magnet coil 8! and main 82. Col] 9! attracts its armature 83 to cause the same to engage the contact 85 to complete the following motor circuit: main 16, armature 83, contact 86, wire 65, motor @2 and main 82. The motor being operated, it will cause the compressor 35 to reduce the temperatures of evaporators 38 and Si and when the temperature of the air at the thermostat 12 decreases to 82 F., the snap switch i l will be opened to break the circuit through the coil 6! whereby the armature 63 will separate from contact 86 and interrupt the motor circuit.

When the relative humidity of the air in the room is below a predetermined maximum value, the suction lines 57 and 55 are interconnected through the pipes 65 and 61', the valve 66 at this time being-open.v Under this condition the pressures of the refrigerants in the evaporators 39 and 3| are substantially the same because either evaporator is connected with both cylinders 36 and 31 of the compressor 35 and consequently the temperatures of both evaporators are substantially the same.

The humidity of the air in the room changes due to changes in the environment and due to the direct adding of moisture to the air and, if the relative humidity of the air is high, a mean temperature of the air at 83 F. would be uncomfortable. In order to rectify this condition, I provide for cooling a part of the air to a low temperature and for this purpose I utilize an instrument preferably a humidostat 81, which is connected in parallel circuit relation with the snap switch 14 through wires 88 and 89. This circuit includes a contact 9| and a movable contact 92 which latter is actuated by an arm 93 of the humidostat 87. When the relative humidity of the air is too high, the humidostat 81 actuates its arm 93 to close contact 92 with contact 9! and thereby completes a circuit to the coil 8| paralleling th circuit including snap switch 14 as follows: main 76, wires Tl and 88, contacts 92 and 9|, wires 89 and i9, switch 80, coil 8i and main 82. It will be apparent therefore that although the temperature of the air is below 82 F. and the snap switch 74 is open, a circuit is completed neverthless through coil 8! to maintain the motor 42 operating when the relative humidity of the air in the room is too high. This condition will cause a prolonged operation of the compressor 32.

In case of a relative high humidity when the air approximates the desired temperature, it is desirable to remove the excess quantity of moisture from the air without materially lowering the temperature of the air. In order to accomplish this, I provide for varying the difierential between evaporators 36 and 38 by increasing the pressure of the refrigerant and likewise the temperature of evaporator 36 and decreasing the pressure of the refrigerant and likewise decreasing the temperature of the evaporator 3!. In this manner, a portion of the heat absorbing means is reduced considerably below the dew point of the air so as to cause a greater precipitation of moisture from the air at this portion. In order to vary the pressures in evaporators 30 and 36, I provide for directly connecting evaporator 3i with the cylinder 36 and for directly connecting evaporator 36 with the cylinder 37 by closing the valve 66. The size of the cylinders 36 and 37 are computed relative tothe sizes of the evaporators 3i and 36 so that, when these evaporators are directly connected to their respective cylinders, the temperature of evaporator 38 will be lowered below the temperature of evaporator 30. The operation of the valve 66 is governed by the humidostat 87. When the relative humidity of the air in the room is above a predetermined desired maximum, the circuit to the electro magnet 69 is interrupted so that the valve 66 is closed. During normal operation, that is when the relative humidity of the air is below a predetermined maximum, the humidostat 8'! is in a position to close a circuit to the coil 69 so as to cause the core 68 to establish intercommunication between suction pipes 55 and 51. The circuit to the electro magnet 69 is traced as follows: main Til, wires 88 and 95, contact 96, movable contact 97, wire 98, electro-magnet 69, wire 99 and main 82. Movable contact 91 is actuated by an arm Hill of the humidostat 87. Thus it is apparent from the foregoing that when the hu- 76 iii) midity of the air is not above a predetermined maximum, the evaporators and 3! operate at substantially the same temperature because the valve M is open and, in case of a relative high humidity, the humidostat 81 operates to prolong the operation of the compressor and establish individual and independent connections between the respective evaporators and cylinders of the compressor whereby to cause an increased precipitation of moisture from the air.

Under some conditions, the relative humidity of the air to be conditioned may be such that the compressor would operate long enough to reduce the temperature of the air to such low degree as to provide an uncomfortably low temperature and, in order to prevent such a condition, I provide for stopping the compressor when the temperature of the air attains a predetermined low value below which temperature the air would be uncomfortable. For this purpose I provide a thermostat i I13 which is connected with the snap switch lit by a tube nu. Bulb I03 and tube it i contain a volatile fiuid which expands and contracts in response to increase and decrease in temperature. When the temperature of the air in the room is decreased, for example, to 76 F.,' the pressure in the bulb I03 and tube Hit is decreased sufliciently to actuate the snap switch til to cause its contacts to be separated. Therefore, regardless whether there is a demand for further dehumidification through the humidostat til, the circuit of coil Bl through the humidostat ti will be broken by switch 80 and armature B3 will separate from contact 84 to interrupt the motor circuit.

The fan 21 and motor 28 operate continuously, the motor being connected to the mains as follows: main 16, wires 11 and I06, motor 28, wires llti and 99 and main 82. x

From the foregoing it will be seen that I have provided a refrigerating apparatus which when employed in an air conditioning system, mamtains a comfortable temperature under proper humidity conditions and in case the relative humidity is too high, the excess moisture is removed from the air without materially lowering the temperature of the air and in case of an extremely high humidity condition, the temperature of the air is lowered but not too cold for comfort or inefficient operation.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within he scope of the claims which follow:

I claim:

1. An air conditioning system comprising in combination, a refrigerating apparatus including an evaporator about which air to be conditioned is circulated, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator about which air to be conditioned is circulated, said second evaporator being connected in a parallel circuit relation with the first mentioned evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said orators, separate conduits connecting the outlets of the evaporators to said means, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to the relative humidity of the air to be conditioned for controlling the flow of refrigerant through the interconnecting conduit.

2. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of evaporators about which air to be conditioned is circulated, each of said evaporators having an expansion valve of the type which is responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the respective evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said refrigerant and delivering the same to said expansion valves, separate conduits connecting the outlets of the evaporators to said means, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to the relative humidity of the air to be conditioned for controlling the flow of refrigerant through the interconnecting conduit.

3. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of evaporators about which air to he conditioned is circulated, each of said evaporators having an expansion valve of the type which is responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the respective evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said refrigerant and delivering the same to said expansion valves, said means having a plurality of suction inlets, a conduit connecting the outlet of one of said evaporators with one of said inlets, a conduit connecting the outlet of another of said evaporators to another of said inlets, a conduit for refrigerant interconnecting said first "mentioned conduits, and means responsive to the relative humidity of the air to be conditioned for controlling the flow of refrigerant through the interconnecting conduit.

4. An air conditioning system comprising in combination, a refrigerating apparatus including a plurality of evaporators about which air to be conditioned is circulated, each of said evaporators having an expansion valve of the type which is responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the respective evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said refrigerant and delivering the same to said expansion valves, said means having a plurality of suction inlets, a conduit connecting the outlet of one of said evaporators with one of said inlets, a conduit connecting the outlet of another of said evaporators to another of said inlets, and means for controlling the rate of flow of refrigerant from one of said evaporators to one of said inlets, said last mentioned means being responsive to the relative humidity of the air to be conditioned.

5. An air conditioning system comprising in combination a refrigerating apparatus including an evaporator about which air to be conditioned is circulated, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator about which air refrigerant and delivering the same to said evap to be conditioned is circulated, said second evaporator being connected in a parallel circuit relation with the first mentioned evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said refrigerant and'delivering the same to said evapora'tors, said means having a plurality of suction inlets, a conduit connecting the outlet of one of said evaporators with one of said inlets, a conduit connecting the outlet of another of said evaporators to another of said inlets, and means for controlling the rate of fiow of refrigerant from one of said evaporators to one of said inlets, said last mentioned means being responsive to the relative humidity of the air to be conditioned.

6. In an air conditioning system, a refrigerating apparatus comprising in combination, an evaporator, an expansion. valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator connected in parallel circuit relation with the first mentioned evaporator, means for withdrawing gaseous refrigerant from said evaporators compressing and condensing the said refrigerant and delivering the same to said evaporators, separate conduits connecting the outlets of the evaporators to said means, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to a condition of the medium cooled by the d evaporators for controlling the flow of refrigerant through the interconnecting conduit.

7. In an air conditioning system, a refrigerating apparatus comprising in combination, a plurality of evaporators each having an expansion valve of the type which is responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the respective evaporator, means for withdrawing gaseous refrigerant from said evaporators compressing and condensing the said refrigerant and delivering the same to said expansion valves, separate conduits connecting the outlets of the evaporators to said means, a conduit for refrigerant interconnecting said first mentioned conduits, and means 40 responsive to a condition of the medium cooled by the evaporators for controlling the flow of refrigerant through the interconnecting conduit.

8. In an air conditioning system, a refrigerating apparatus comprising in combination, an

evaporator, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator connected in parallel circuit relation with the first mentioned evaporator, means for Withdrawing gaseous refrigerant from said evaporators compressing and condensing the said refrigerant and delivering the same to said evaporators, said means having a plurality of suction inlets, a conduit connecting the outlet of one of said evaporators with one of said inlets,

a conduit connecting the outlet of another of said evaporators to another of said inlets, and means responsive to a condition of the medium cooled by the evaporators for controlling the flow of gaseous refrigerant to one of said inlets.

9. In an air conditioning system, a refrigerating apparatus comprising in combination, an evaporator, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator connected in parallel circuit relation with the first mentioned evaporator, means for withdrawing gaseous refrigerant from said evaporators compressing and condensing the said refrigerant and delivering the same to said evaporators, said means having a plurality of suction inlets, a conduit connecting the outlet of one of said evaporators with one of said inlets, a conduit connecting the outlet of another of said evaporators to another of said inlets, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to a condition of the medium cooled by the evaporators for controlling the flow of refrigerant through the interconnecting conduit.

10. An air conditioning system comprising in combination, a refrigerating apparatus including an evaporator about which air to be conditioned is circulated, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator about which air to be conditioned is circulated, said second evaporator being connected in a parallel circuit relation with the first mentioned evaporator, means for withdrawing gaseous refrigerant from the evaporators compressing and condensing the said refrigerant and delivering the same to said evaporators, separate conduits connecting the outlets of the evaporators to said means, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to a condition of the air to be conditioned for controlling the flow of refrigerant through the interconnecting conduit.

11. An air conditioning system comprising in combination, a refrigerating apparatus including an evaporator about which air to be conditioned is circulated, an expansion valve responsive to the condition of the refrigerant in the evaporator for controlling the flow of refrigerant to the evaporator, a second evaporator about which air to be conditioned is circulated, said second evaporator being connected in a parallel circuit relation with the first mentioned evaporator, heat dissipating means including means for circulating refrigerant through the first evaporator for maintaining the same at a certain temperature and means for circulating refrigerant through the second evaporator for maintaining the second evaporator at a different temperature, a conduit connecting the outlet of the first evaporator with the first mentioned circulating means and a conduit connecting the outlet of the second evaporator with the second mentioned circulating means, a conduit for refrigerant interconnecting said first mentioned conduits, and means responsive to a condition of the air to be conditioned for controlling the flow of refrigerant through the interconnecting conduit.

12. The method of controlling the humidity and temperature conditions of air by a mechanical refrigerator employing refrigerant compressing and condensing means and evaporating means including a plurality of evaporators connected at all times in parallel circuit relation, which method comprises, causing air to circulate over the evaporating means; causing the starting of operation of the compressing and condensing means in response to a high temperature condition or a high humidity condition of the air; and while the compressing means is in operation, varying the refrigerating effect of the evaporating means by controlling the fiow of refrigerant through one of the evaporators in accordance with changes in one of the said conditions of the air.

LAWRENCE A. PHILIPP. 

